The present invention relates to an air curtain system for a refrigerated case. The present invention more specifically relates to a secondary air curtain system for an open-front refrigerated case. The present invention more specifically relates to a secondary air curtain system that recycles ambient air cooled by a primary layer of an air curtain for use as a secondary layer of the air curtain. The present invention also relates to an air curtain system that provides supplemental cooling and/or dehumidification of a stream of ambient air for discharge over a front portion of a case.
It is known to provide for a refrigerated case for storage and presentation of food products (such as perishable meat, dairy, seafood, produce, etc.). Such known refrigerated cases may include those of a type typically having an open front to permit consumers to reach in and select products from shelves within the case (e.g. “self service” type cases, etc.). Open-front refrigerated cases often have an “air curtain” extending across the front of the case and is made of one or more layers of refrigerated air that flow downwardly from a discharge along a top front portion of the case and is drawn into a return along a lower front portion of the case (for example, at or inside of a front “bumper” of the case). The air curtain is intended to form an “invisible boundary” between the product display area within the case and the ambient air surrounding a front of the case. The invisible boundary of the air curtain is intended to minimize “mixing” of surrounding ambient-temperature air with the chilled air within the case and behind the air-curtain. However, the warmer ambient air surrounding the case tends to become entrained within the air curtain, becoming cooled by the air curtain and tends to “spill” or flow down over the front of the case.
Such open-front cases having an air curtain often include at least one layer (e.g. a “primary” layer) of air that is refrigerated or chilled by the case and discharged downwardly across a front of the case. Such open-front cases may also include a second or third layer of air (e.g. “secondary” and “tertiary” layers) adjacent the primary layer to help improve the efficiency of the primary layer of air in the air curtain. These secondary or tertiary layers are often formed using a fan that pulls ambient air from above the refrigerated case and discharges such ambient air outwardly adjacent to the primary layer. However, such known air curtains for open-front cases have certain disadvantages. For example, ambient air that becomes chilled by the primary or refrigerated air curtain often “spills” over the front bumper of the case and is not returned to the case for continuing use in the air curtain and is typically “lost” to the ambient environment. Further, using ambient air (or air that is slightly warmer than the ambient environment) as a secondary or tertiary layer is less likely to improve the efficiency of the primary layer of air in the air curtain than if the secondary or tertiary layer was at least slightly cooler than the ambient environment.
Accordingly, it would be desirable to provide a refrigerated case with an open front having an air curtain with a primary layer formed from air refrigerated by the case. It would also be desirable to provide an air curtain system having a secondary layer of air formed from air cooled by exposure to the primary layer and that is not returned to the primary layer. It would further be desirable to provide an air curtain system having a primary layer of refrigerated air and a secondary layer of air formed from the air cooled by exposure to the primary layer and that spills over a front bumper of the case. It would also be desirable to provide an air curtain system having a primary layer of air refrigerated by the case and a secondary layer of “cool” air that is recycled from a front of the case for use in providing a “buffer” layer of air having a temperature lower than an ambient temperature. It would be also be desirable to provide an air curtain system that provides supplemental (e.g. additional or further) cooling of the recycled ambient air that forms the secondary curtain. It would be further desirable to provide an air curtain system that dehumidifies the recycled ambient air that forms the secondary air curtain.
Accordingly, it would be desirable to provide an air curtain system for a refrigerated case having an open-front and air curtain having any one or more of these or other advantageous features.